Multichambered fired heater and tube wall construction



Dec. 20, 1966 M. A. ZIMMERMAN 3,292,599

MULTICHAMBERED FIRED HEATER AND TUBE WALL GONSTRUCTON Filed Dc. 14.1964,

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United States Patent O 3,292,599 MULTICHAIVIBERED FIRED HEATER AND TUBEWALL CONSTRUCTION g g Merle A. Zimmerman, Shreveport, La., assignor vtoWaste Heat Engineering Corp., a corporation of Texas Filed Dec. 14,1964, Ser. No. 418,225 4 Claims. (Cl. 122-510) The present inventionrelates to a multichambered tired heater and to a tube wall constructiontherefor.

Various forms of lluid heaters have been heretofore proposed, such byway of example that as shown in United States Patent No. 2,396,200. Thepresent invention may be considered an improvement of the tubearrangement and tube wall construction for heaters such as thatillustrated in Letters Patent 2,396,200 as will be more fully describedhereinafter.

In the heating of lluids such as hydrocarbon oils and the like, it isdesirable to accomplish the heating of the fluids in a manner to avoidundesirable effects thereon. To accomplish this, it is desirable thatthe heating of the fluids be substantially uniform and not occur inlocal areas on the tubes through which the fluid is conducted whichlocalized heating causes hot spots which may cause deleterious effectson thel fluid being heated.

Also, it is desirable to accomplish heating of the fluids whilesimultaneously avoiding flame impingement upon the tubes through whichthe iluid is flowing to reduce the possibility of forming hot spots, andto conduct the combustion or heating gases adjacent the tubes andthrough the heater in a manner to eflciently and properly accomplish theheating of the fluids.

An object of the present invention is to provide a multichambered tiredheater in which several streams of iluid may be heated under controlledtemperature conditions simultaneously and to heat the tubes from bothsides in a manner to produce a very uniform heat transfer rate ofgreater intensity than that commonly allowable when the tubes are heatedfrom one side only or from both sides. Such construction providessuperior heating characteristics and at the same time permits asubstantial savings in costs through the reduction in the number oftubes and the saving in heater construction costs.

Another object is to form a multichambered fired heater with rows oftubes which inhibit the passage of heating gases through the rows oftubes and thereby reduces the possibility of flame impingement directlyon the tubes. i

Another object of the present invention is to provide a construction andarrangement of tubes in a heater to form a wall and thereby divide theheater into multichambers with burners therein to heat each side of thetubes uniformly.

Still another object of the invention is a tube wall construction todivide a heater into -a number of chambers, each chamber having aplurality of burners therein for heating the tubes, and the tubes beingconnected together to inhibit combustion gases passing between thetubesand thereby avoid llame impingement upon the tubes.

Another object of the present invention is to connect a plurality oftubes together to form a dividing wall in a fired heater in a manner toheat the tubes to produce a uniform heat transfer rate.

Other objects and advantages of the present invention will become morereadily apparent from consideration of the following description anddrawings wherein:

FIG. 1 is a schematic representation of a heater embodying the presentinvention; and

FIG. 2 is an enlarged sectional view showing one form of the tube wallof the present invention.

Attention is rst directed to FIG. 1 of the drawings wherein a structureis referred to generally by the numeral ICC 2. The structure 2 forms asuitable enclosure to accomplish the purposes of the present invention,such structure being formed of suitable refractory material such as firebrick or the like. The construction of the structure 2 is not criticalto the present invention and any suitable well-known and standardpractice of forming the structure 2 may be employed.

The structure 2, by reason of its closed end, bottom, top, and sidewalls, as will be described in greater detail, forms a space referred togenerally by the numeral 3. It will be noted that a plurality of spacedrows of tubes illustrated at 4 are provided in the space 3 to divide thespace 3 into separate chambers 5, 6, 7, 8 and 9. Of course, the tubes ineach row are joined at their ends to form a continuous lluid conductingpath in that row.

Burners 11 are mounted in each of the chambers 5, 6, 7, 8, and 9 asillustrated for heating the spaced rows 4 of tubes on each side thereof.

It can be appreciated that the rows of tubes 4 are formed by tubes 15which are connected together, as will be described in greater detailhereinafter, to form continuous divider Walls between the chambers 5, 6,7, 8, and 9, and the tubes 15 also serve to conduct lluid therethroughwhich fluid is heated by the burners 11 in the various chambers. Flues5a, 6a, 7a, 8a and 9a are formed in the structure 2 which communicatewith the chambers 5, 6, 7, 8 and 9, respectively, at their upper endsand also communicate with the common discharge 18 which is connected tothe stack 19 for discharge of the combustion gases from the structure 2.

If desired, iluid conducting tubes may also be provided as illustratedat 20 adjacent the fines 5a, 6a, 7a, 8a and 9a so that as the combustiongases from the burners 3 are conducted to the ues 5a, 6a, 7a, 8a and 9a,heating of the tubes 20 and the uid flowing therethrough may beeffected.

A convection tube section 19a is arranged below the stack 19 asillustrated in the drawings, FIG. 1 for heating of fluid therein by thestack gases. It can be appreciated that the convection tube section 19a,tubes 20 as well as the tubes 15 are mounted in the structure 2 so thatfluid is conducted therethrough in a well-known manner for heatingthereof. If desired, the convection section 19a, the tubes 20 and thetubes 15 may be connected in series, so that the fluid is firstpre-heated in convection section 19a and tubes 20 and then conducted totubes 15 for final heat. In some instances, convection section 19a mayserve as a preheater for a iluid stream which is then conducted to tubes20 for final heat. The spaced rows of tubes 4 may be also connected toreceive and heat separate iluid streams. For example tube row 4a may beconnected to receive one uid stream, tube rows 4b and 4c may beconnected in series to receive a second uid stream, and tube row 4d maybe connected to still a third fluid stream for heating thereof. In thisevent, the burners 11 in chambers 8 and 9 will lbe provided withsuitable controls by means well known in the art to maintain the desiredtemperature in chambers 8 and 9 so as to heat the fluid in tube row 4ato the desired temperature. Similarly, the burners in chambers 5 and 6heat tube wall 4d and the burners in chambers 6, 7 and 8 heat tube walls4b and 4c.

Of course, any suitable number of chambers and tube rows may beprovided, depending upon the size of the heater.

The structure 2 includes end and side walls and a bottom and top of anysuitable construction well known. The combustion or heating draft -gasesare generated by the burners 11 and then flow through the chambers toaccomplish their heating function and are then discharged out the upperend of each chamber and into common discharge 18 to be discharged fromthe structure through their upper end 28 in any suitable manner such asby bolting or the like to the structure 2 at 29. They are then permittedto hang downwardly and a receptacle 30 formed by the guide walls 32 and33 receives an extension 30a.

formed on the lower end of the rows 4 so that the spaced rows 11 uponheating may extend downwardly towards the receptacle 30.

A form of the tube wall is shown in FIG. 2 of the drawings and is shownas including tubes 15 which are provided with ns 35 formed on each sidethereof and connected vided with suitable refractory material 36 ontheir surfaces v between the tubes 15 as shown in FIG. 2 of the drawingsto inhibit overheating of the tubes 15 at the point where the ns 35 areconnected with the tubes.

It can be appreciated that the construction as well as the arrangementof the tube Wall 4 in the heater 2 substantially prevents communicationor passage of heating gases from one chamber to the next in thestructure such as described with regard to FIG. 1 of the drawings. Thus,the combustion or heating gases from the burners 11 are communicatedupwardly in the chamber rather vthan around the tubes and .the flow ofheating gases elected by the construction of the tube wall 4, as Well asits arrangement in the structure 2 in relation to the ilue of eachrespective chamber and the stack 19 tends to more evenly and properlydistribute the draft gases adjacent the tubes 15 and thereby uniformlyheat the tubes at a greater intensity than heretofore possible. Also,the continuous tube Wall 4 substantially, if not completely, eliminatespassage of the heating gases between the tubes 15 in the tube wall fromone chamber to the next and thereby pre-` vents the llame from theburner 11 from coming into diface for a process heater which isimpervious to :the ow vof heating gases from one chamber to the next.

Under some circumstances, it may be desirable to provide an expansionjoint which is formed in the dividerV wall 14 formed by the tubes 15 andtheir interconnecting ns 35, and this may be accomplished by forming aslot 40 in one or more of the tins 35 and securing a pin 41 in anadjacent overlapping fin. An enlarged end 42 mayA be formed on the pin41 after it has been positioned in the slot 40 and the refractorymaterial then formed to accommodate free longitudinal movement of thepin 41 relative to 4the slot 40, it being noted that the diameter of thepin 41 is less than the length of the slot 40 to accomodate relativemovement therebetween. Upon expansion or extension of the wall 4 byreasonof heating, the overlapping fins 35 may move relative to eachother and thereby accommodate extension of the tube wall 4 withoutrupturing or deforming the wall 4. The tube wall 4 is constructed sothat the axes` of the tubes 15 are substantially in alignment, orsubstantially in a common plane.

Broadly, the present invention relates to a multichambered fired heaterand to a tube wall construction therefor.

What is claimed is:

1. A tube wall partition for a multichambered tired heater comprising:

(a) a plurality of hollow tubes having their axes lying substantially ina common plane;

(b) unitary metallic tins extending outwardly from said tubes;

(c) means interconnecting adjacent tubes together by said tins to form asubstantially vertical wall;

(d) refractory material secured on each side ofl said fins between saidtubes to inhibit overheating of said tubes where joined with said lins;

(e) means for supporting the uppermost tube from inside of the heater;

(f) said fins between said tubes supporting and suspending said tubesbelow the uppermost tube.

2. The structure as set forth in claim 1 including an expansion jointformed by said ns to accommodate longitudinal expansion of the tubewall.

3. The structure as set forth in claim 2 wherein said expansion joint isformed by providing slot means in one of said ns, and pin meansconnected with an adjacent overlapping fin, said Ipin means tting insaid slot means and having a diameter less than the length of said slotto accommodate longitudinal movement of said tube wall.

4. The structure as set forth in claim 1 including means with thelowermost tube and the heater to serve as a guide for the downwardexpansion of said tubes.

References Cited by the Examiner UNITED STATES PATENTS 1,836,603 12/1931Ladd 122-235 2,108,397 2/ 1938 Watts --..Q 122-356 X 2,293,735 8/ 1942Hardgrove 122-6 2,456,786 12/ 1948 Kniel et al. 122-356 3,160,144 12/1964 Daman 122-235 KENNETH W. SPRAGUE, Primary Examiner.

1. A TUBE WALL PARITITION FOR A MULTICHAMBERED FIRED HEATER COMPRISING:(A) A PLURALITY OF HOLLOW TUBES HAVING THEIR AXES LYING SUBSTANTIALLY INA COMMON PLANE; (B) UNITARY METALLIC FINS EXTENDING OUTWARDLY FROM SAIDTUBES; (C) MEANS INTERCONNECTING ADJACENT TUBES TOGETHER BY SAID FINS TOFORM A SUBSTANTIALLY VERTICAL WALL; (D) REFRACTORY MATERIAL SECURED ONEACH SIDE OF SAID FINS BETWEEN SAID TUBES TO INHIBIT OVERHEATING OF SAIDTUBES WHERE JOINED WITH SAID FINS;